1. Field of the Invention
The present invention relates to a socket for a pipe coupling with respect to which a plug can quickly and easily be connected/disconnected.
2. Description of the Related Art
A pipe coupling comprising a socket, including a valve, and a plug has heretofore been known. With this pipe coupling, since fluid pressure in the socket forms a large connection load in connecting the socket to the plug, it becomes difficult to connect the socket to the plug. Moreover, during disconnection of the socket from the plug, with fluid remaining in the plug, there is a possibility of the plug jumping out by the fluid pressure. A socket for a pipe coupling has been proposed so as to solve the problem and facilitate connection and disconnection of the socket to and from the plug.
This type of socket for the pipe coupling has been disclosed in which a ball valve is used as a valve disposed in the socket, and a sleeve for plug connection and a sleeve for valve opening/closing operation are fitted into the outer periphery of the socket main body (Jpn. Pat. Appln. KOKAI Publication No. 2001-116178). When the plug is disconnected, the sleeve for valve opening/closing operation is moved backwards. While the sleeve moves backwards, the valve closes, and the fluid in the plug is discharged to the outside. Furthermore, when the sleeve for valve opening/closing operation is moved backwards, the sleeve for plug connection accordingly moves backwards to perform an unlocking operation of the plug. Thereby, the plug can be disconnected from the socket for the pipe coupling.
According to the above-described socket for the pipe coupling, during the connection of the socket and plug, the socket and plug can be connected to each other without being influenced by the fluid pressure in the socket. Moreover, during the disconnection, the socket and plug can be disconnected after the fluid in the plug is discharged. Therefore, the socket and plug can easily be connected/disconnected. However, the structure is complicated, the number of components is large, and the manufacturing cost therefore is high. Furthermore, the valve is opened/closed by moving the sleeve for valve opening/closing forwards/backwards. Therefore, the entire constitution is lengthened and enlarged, and there has been a demand for improvements.